This invention relates generally to medical imaging systems, and more particularly, to determining the time from onset to aortic valve closure using cardiac imaging.
Diagnosis of wall motion abnormality of the left ventricle may be performed using parametric imaging. One parameter that may be used is peak systolic strain (PSS), which is defined as the peak negative strain during systole. Determining the PSS requires knowing the timing of end-systole, or in other words, the timing of the aortic valve closure.
Aortic valve closure is a cardiac event that is relatively difficult to determine using gray-scale imaging. There are several methods that have been used that require operator expertise and interaction. One method has the operator position a Doppler curser to detect blood flow through the aortic valve. When no flow is present, the aortic valve is closed. However, the flow measurement is usually not simultaneous with the 2D measurements on which the strain analysis is based, and the heart rate between the measurements can vary to the extent that the aortic valve closure that is measured is not relevant for the strain based parametric imaging being used. Another method has the operator view the aortic valve on a monitor, such as in an apical long axis view (APLAX). The time of closure of the aortic valve is then determined by viewing the leaflets of the valve and identifying the correct frame of data. Unfortunately, the leaflets, as well as the aortic valve itself, are often difficult to view. These methods may be time consuming and may not result in the desired information.
Therefore, a need exists for minimizing the operator time and expertise needed when determining the time to aortic valve closure.